A known drive unit disclosed in JP2004-122979A (hereinafter referred to as Reference 1) is provided with a terminal block connecting a motor coil of a motor to an external device. The drive unit includes the motor (rotating electrical machine), a terminal box, and the like that are accommodated within a housing main body (motor case). The housing main body is divided into a gear box and a motor case. The gear box includes therein an oil chamber. The motor case accommodates therein the motor having a rotor and a stator that includes the motor coil. The terminal block is arranged at an outer circumferential portion of the gear box of the housing main body, that is, the terminal box accommodating therein the terminal block is arranged at the outer circumferential portion of the gear box. An opening portion in connection with the motor case of the housing main body and a fitting hole in connection with an external atmosphere of the housing main body are formed in the terminal box. A distributor wire is connected to an end portion of the motor coil. Further, the distributor wire is inserted in the opening portion by penetrating therethrough so as to be connected to the terminal box. A feeder wire connected to an inverter and the like is inserted in the fitting hole by penetrating therethrough. Further, the feeder wire is connected to the terminal box in a condition where a connecting end portion of the feeder wire is fitted in the fitting hole, thereby being fixed to the terminal box along with the distributor wire. In addition, the terminal box is connected to an oil pool chamber, which is formed at an outer side of the oil chamber in the gear box, via a connecting passage connecting to the oil pool chamber.
For example, in the drive unit according to Reference 1, the motor driving wheels for a hybrid vehicle includes a clutch mechanism accommodated in the gear box of the housing main body and operated by hydraulic pressure. An operating oil for operating the clutch mechanism is stored in the gear box. When the rotor rotates, the operating oil stored in the gear box may leak therefrom and spatter within the housing main body. As described above, the opening portion is formed in the terminal box and the terminal box is connected to the oil pool chamber of the gear box via the connecting passage. Accordingly, the operating oil that is spattered within the housing main body may penetrate into the terminal box through the opening portion and the connecting passage and therefore is attached to the terminal block. As a result, the terminal block may corrode because of moisture and the like included in the operating oil.
As described above, the terminal box connects the distributor wire to the feeder wire that is connected to the inverter and the like. For example, when the motor is checked for maintenance and repair, the feeder wire is often detached/attached from/to the inverter and the like. Accordingly, in a case where the terminal block is corroded by the operating oil spattered within the housing main body, an electrical contact failure may occur in the motor.
A need thus exists for a rotating electrical machine, which is not susceptible to the drawback mentioned above.